For a home of 1,500 to 2,500 square feet with existing ductwork, OniFix's current range for a standard central air conditioning system is $6,500 to $11,000. A high-efficiency system adds roughly $2,000 to $5,000. If the house has no ducts and they have to be added, that's another $3,500 to $8,000, so a standard system with new ductwork in a house that size typically runs $10,000 to $19,000.
Home size moves the base figure. Under 1,500 square feet the standard range is about $5,500 to $9,400; from 2,500 to 3,500 square feet it's about $7,800 to $13,200, and above 3,500 square feet about $9,100 to $15,400. These are typical ranges today, not a quote. The exact price is confirmed after a visit, and you have it before any work starts. The rest of this article covers what moves a job around within those ranges.
System size, in tons
Air conditioners are sized in tons of cooling, where one ton is 12,000 BTUs per hour. The right size comes from a load calculation (ACCA's Manual J is the standard method) that accounts for the house's square footage, insulation, windows, shading and which way it faces. Bigger isn't better. An oversized air conditioner cools the air quickly and shuts off before it has run long enough to pull much moisture out, which leaves the house cool but clammy on a humid July day. It also costs more to buy. If the old system never kept up, or the house has changed since it went in, don't assume the old size was right.
Efficiency: SEER2 and the federal minimum
Cooling efficiency is rated in SEER2, a seasonal measure based on a revised federal test procedure that took effect in 2023. The higher the number, the less electricity it takes to deliver the same cooling. SEER2 and the older SEER ratings aren't directly comparable, so compare SEER2 to SEER2. Massachusetts is in the Department of Energy's northern region, where the minimum for a split-system central air conditioner manufactured since January 1, 2023 is 13.4 SEER2. ENERGY STAR certification for a split central air conditioner requires at least 15.2 SEER2 and 12.0 EER2.
Moving up from a standard system usually means a two-stage or variable-speed compressor that runs longer at lower output. You get quieter operation and better humidity control along with lower electric bills. Whether the extra $2,000 to $5,000 pays for itself depends on how much you run the air conditioning, and in Massachusetts the cooling season is short next to the heating season. For many households, the comfort is as strong an argument as the savings.
Replacing the indoor coil along with the outdoor unit
A central air system has two halves: the outdoor condensing unit and the indoor evaporator coil, which usually sits on top of the furnace or inside an air handler. The efficiency rating belongs to the pair. AHRI, the industry group that certifies these ratings, certifies the combination rather than each unit, and a new outdoor unit connected to an old coil may not deliver the rating on its label. That's why most replacements include a new coil, and why fitting it to the furnace, sometimes with a sheet metal transition, is part of the price. If the furnace is near the end of its life too, replacing both at once avoids paying for that transition work twice and gives you equipment designed to work together.
The refrigerant change, and what it means if only half the system fails
Under the federal AIM Act, the EPA's Technology Transitions rule requires new residential split air conditioners and heat pumps manufactured or imported since January 1, 2025 to use refrigerants with a global warming potential below 700. R-410A, the refrigerant in most central air systems installed over the past 15 years or so, doesn't meet that limit. New equipment uses lower-GWP refrigerants such as R-454B and R-32, both listed by the EPA as acceptable for new residential systems. Both are classified A2L, meaning lower flammability, so the equipment is built to an updated safety standard and installers follow handling procedures to match. Systems built entirely from R-410A components made before 2025 can still be installed, but new production has moved on.
If your system runs on R-410A, nothing forces you to replace it. The EPA's rule is forward-looking: existing systems can keep running and be repaired, and components for repairing them, including a replacement condensing unit, aren't restricted, though the EPA notes that availability may lessen over time as these refrigerants are phased down. So if a fairly young R-410A system loses its outdoor unit, a like-for-like replacement may still be possible and is worth asking about. If the system is older, or the coil is also worn, a full replacement usually makes more sense. A new-refrigerant outdoor unit needs an indoor coil built for the same refrigerant, and whether the existing refrigerant lines can be reused depends on their size, their condition and the manufacturer's instructions.
Older systems that still run on R-22 are an easier decision. No new R-22 has been made or imported in the U.S. since January 1, 2020, so a major failure on one of those systems is usually the signal to replace it. Whatever the refrigerant, the work falls under EPA Section 608, and technicians who handle refrigerant need Section 608 certification. OniFix's owner is EPA 608 certified, and it's a fair question to ask of anyone working on your system.
Ducts: whether you have them, and what shape they're in
A house with a furnace already has ducts, but they were usually sized for heating. Cooling often needs more airflow, so returns that were fine for heat can be too small for air conditioning, and ducts in an attic or unconditioned basement lose cooling along the way if they're leaky or uninsulated. Fixing that is often modest work, and it's easiest to do at the same time as the equipment.
Houses heated by boilers, with radiators or baseboard, are a different project, and they're common around here: in Everett, Newton and Watertown, more than four in ten homes were built before 1940. Adding central air to a house without ducts is where the $3,500 to $8,000 ductwork add comes in, and where your house falls in that range depends on how easily ducts can be routed through it.
Attic air handlers
A common way to add central air to a house without ducts is an air handler in the attic, feeding ceiling vents in the rooms below with a return in a central hallway. It works well for the upstairs, usually the hottest part of the house, though cooling the first floor may take a second system or ducts run through closets. Attic work costs more than basement work. The equipment comes up through a hatch or pull-down stairs, the ducts need good insulation in a hot attic, and the air handler should sit in a secondary drain pan with a shutoff switch so a clogged drain can't leak through the ceiling. Replacing an existing attic air handler brings the same access questions.
If running ducts through finished rooms doesn't appeal, ductless mini splits are the usual alternative. Our article on cooling an old house without ductwork goes through the options, and the mini split vs. central air comparison puts the two side by side.
Electrical work and permits
The outdoor unit needs a dedicated 240-volt circuit and a disconnect within sight of the unit. When an existing system is being replaced, that circuit is usually already there and may only need updating for the new unit. A first-time installation needs a new circuit, and an older or full panel may need an upgrade. In Massachusetts this work is done by a licensed electrician under a permit and checked by the town's wiring inspector. Depending on the town, the installation may also need a building permit, so ask how permits are handled when you compare quotes.
Central AC or a heat pump?
A heat pump is an air conditioner that can run in reverse. In summer it cools the same way central AC does; in winter it heats. So if you're replacing central air, it's worth pricing a heat pump alongside it. Using the same typical ranges, a ducted heat pump for a 1,500 to 2,500 square foot home runs $11,000 to $20,000, against $6,500 to $11,000 for standard central AC, so the heat pump costs more up front.
Incentives push the other way. Mass Save's heat pump rebates don't apply to a cooling-only air conditioner, and its 0% HEAT Loan covers heat pump projects but not central AC. A heat pump installed alongside a furnace or boiler that stays in place can qualify for Mass Save's partial-home rebate, $1,125 per ton in 2026 (dropping to $1,000 on January 1, 2027), provided it has an integrated control, qualifying cold-climate equipment and a contractor in the Mass Save Heat Pump Installer Network. Neither gets a federal tax credit in 2026: the 25C credit, which covered both, ended with 2025. Our breakdown of heat pump costs in Massachusetts runs through the numbers.
Plan before the first heat wave
The worst time to shop for central air is the first 90-degree week of summer. The house is hot, contractors are at their busiest, and it's hard to weigh quotes carefully when you just want the cooling back. Spring, or even the fall before, gives you time for a load calculation, a real look at efficiency or a heat pump, and an install date that suits you. If your system is over 15 years old, still runs on R-22 or needed repeated repairs last summer, that's a reason to price a replacement before you need one. The AC installation page explains how the job is handled, from the first look at your house to checking the cooling at the vents.
For a range based on your own home size, efficiency choice and ductwork, try the instant price tool. It takes about a minute, and the exact price comes after a visit, before any work starts.
Sources: U.S. Department of Energy, 2023 central air conditioner standards FAQ; ENERGY STAR, central air conditioner and heat pump specification; AHRI, certified ratings; EPA, Technology Transitions restrictions by sector; EPA, HFC phasedown questions; EPA, SNAP substitutes for residential AC and heat pumps; EPA, R-22 questions for homeowners; Mass Save, air source heat pump rebates; IRS, Energy Efficient Home Improvement Credit.